Why does the church focus so much on numbers?
"Oh no we don't, we are really concerned about the spiritual development of our congregation". Of course the demonstration of this is a commitment to the church, and involvement in the programs of the church, which are about getting more people into church. And that is the real focus of the church work - more people in church.
When a church is looking at how successful events have been, what do they look at? Numbers. Because numbers are an easy way of quantifying results. Even if it isn't a good way, it is easy, and it provides one way of assessing it, surely? Numbers indicate how many people engaged with the event, how many felt it to be a good idea? That is important, surely?
The answer to all of that is, no. Numbers are not important. All that they indicate are how popular events are. If you want to get people into church, then leave a fiver on each pew. It will be popular, it will get people into church, but it will not be the right thing to do, because it will not help people engage more with God. And so many church events are not really that different to a fivers on the pews approach. Yes, they get people in, but do they help the real work of the church - helping people to engage with God, helping people find and experience and explore God? Often the answer is no, and sometimes the answer is no, because they do the opposite, and drive people away from God instead.
One of the interesting results I have found in my research is that, whatever the criteria for assessment, that is what people will work to. In a work situation, if you assess people on the basis of, say, number of calls made, then the staff will be making lots of calls, whether they are successful calls or not. If you assess people on the basis of sales made, then sales will increase, irrespective of the value of those sales. And quick sales will be valued above hard-won sales, even though the latter may be better in the long term.
In the same way, if a church establishes the "success criteria" to be "number of people in church", then the congregation will either work towards getting people into church anyway they can; or leave having rejected the basis on which that church exists, because it is not the right reason for the existence of the church.
Focussing on numbers is wrong, however it is done. Setting the wrong "success criteria" for a church will lose people. The only right criteria is that people are engaging with God, experiencing God. That is a very difficult thing to measure, especially in the short term. It does not help measure the success of an event, but on the life of the church over a long time.
Or maybe forget about the "success criteria" concept altogether.